Count the take-ins and every other background work in the serving group, so serve's stop waits for them too (issue 1945)

inBackground ran the take-ins of done keys (now in #463's slots), the start's
look, the given values' replacement and the announced reads beside serve without
serve waiting for them: a take-in could outlive its controller as the loops did.
It now takes the context and is counted in its serving group as well, and a
serve that is stopping starts none.

cmd/mesh-controller/composed_keys.go

@@ -307,7 +307,7 @@ func watchDoneKeys(ctx context.Context, open *stores) {
 		return
 	}
 	if err := builderkeys.Watch(ctx, keys.JS, func(module string) {
-		inBackground(func() { takeDoneKey(ctx, open, module) })
+		inBackground(ctx, func() { takeDoneKey(ctx, open, module) })
 	}); err != nil {
 		closeKeys()
 		fmt.Printf("done keys: the builder's keys are not watched: %v\n", err)
@@ -318,7 +318,7 @@ func watchDoneKeys(ctx context.Context, open *stores) {
 		closeKeys()
 	})
 	// And every module once now, after the watch is open so no write falls between the two.
-	inBackground(func() {
+	inBackground(ctx, func() {
 		doneKeysAtStart(ctx, catalogedModules(open), func(module string) { takeDoneKeyAtStart(ctx, open, module) })
 	})
 }
@@ -389,7 +389,7 @@ func takeDoneKeyAtStart(ctx context.Context, open *stores, module string) {
 	_, again := doneKeysLookAgain.LoadAndDelete(module)
 	if err != nil || again {
 		// A failure, a wait or a wake meanwhile is followed by takeDoneKey, which says it and looks again.
-		inBackground(func() { takeDoneKey(ctx, open, module) })
+		inBackground(ctx, func() { takeDoneKey(ctx, open, module) })
 	}
 }